Mass-spectrometric analysis of polymers based on furyl alcohol-polyamic acid compositions

Polymer compositions based on furyl alcohol and polyamic acid were investigated by using mass-spectrometric thermal analysis. It was established that polyamic acid catalyses both the polycondensation of furyl alcohol and the formation of a three-dimensional network of furan polymer.

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Zusammenfassung Mittels massenspektroskopischer Thermoanalyse wurden auf Furylalkohol und Polyamidsäure basierende Polymergemische untersucht. Es wurde festgestellt, daß Polyamidsäure sowohl die Polykondensation von Furylalkohol als auch die Bildung eines dreidimensionalen Furanraumnetzes katalysiert.

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Angular distribution of electrons behind barriers comparable to the extrapolated range

A study is reported of the angular distribution of monoenergetic electrons from a betatron which have traversed barriers of Al, Cu, and Pb with thicknesses reaching the extrapolated range. The initial electron energy is in the range 3–8 MeV. The experimental results agree well with Monte Carlo calculations carried out for identical calculations and with the results of earlier work for smaller barriers. The half-width of the electron angular distribution, increasing with increasing barrier thickness, reaches a nearly constant value, while the distribution itself corresponds to the laws of complete diffusion, i. e., converts into a distribution similar to cos². As the thickness of the absorbers is increased further, the half-width decreases and the distribution becomes narrower, due to the penetration far into the absorbers of electrons which have been scattered predominantly in the forward direction.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 35–38, May, 1975.     

Evolution of the temperature field on an absorber irradiated by an intense ion beam

Using the small parameter method, a numerical solution is found for the nonlinear thermal conductivity equation describing evolution of the temperature field in an absorber after completion of a radiation pulse. High speed (10⁶ K/sec) heating of the surface layers over 1·10^–5 sec is observed. Absorber cooling parameters are obtained as a function of time and distance from the irradiated surface.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 5, pp. 89–93, May, 1986.     

Pyrylocyanines. 23. 2-Pyrylocarbocyanines with substituents in hetero residues

Symmetric 2-pyrylo- and asymmetric (indo)(2-pyrylo)trimethinecyanines with substituents of different electronic nature in the pyran residue were synthesized. The influence of the conjugation effect and inductive effect on the characteristics of absorption bands of the synthesized dyes was analyzed by a quantum chemical calculation according to a common MO Hückel method.For Communication 22, see [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii No. 12, pp. 1607–1613, December, 1986.     

Synthesis and steric structure of 1,3(1,5)-dimethyl-2-phenyl-and -2,4-diphenyl-4-piperidols

1,3(1,5)-dimethyl-2-phenyl- and -2,4-diphenyl-4 piperidols were respectively obtained with the reaction of 1,3-and 1,5-dimethyl-2 phenyl-4-piperidoraes with sodium borohydride and phenyllithium. The steric isomers of the compounds obtained were separated and identified by spectral methods.Moscow State Academy of Precision Chemical Technology, Moscow 117571. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 941–945, July, 1994. Original submitted July 11, 1994.     

Synthesis of substituted 4-acetylamino-4-phenylpiperidines from the corresponding 4-piperidols under Ritter reaction conditions

The reaction of substituted 4-phenyl-4-piperidols with acetonitrile under Ritter reaction conditions leads to formation of mixtures of the corresponding 4-acetylamino-4-phenylpiperidines and 1,2,5,6-tetrahydropyridines, from which we isolated the target amides by fractional crystallization.M. V. Lomonosov State Academy of Fine Chemical Technology, Moscow 117571. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 776–780, June, 1997.     

Molecular polarizability of organic compounds and their complexes: LII. Molar volumes of polymeric compounds in solutions,extrapolated to infinite dilution,and steric structure of their molecules

The molar volumes in solutions at infinite dilution were determined for a series of vinyl, glycol, isoprene, and cyclopentadiene polymers and oligomers with various degrees of polymerization. An additive analysis of the molar volumes showed that molecules of vinyl, ethylene glycol, and isoprene polymers exist in solutions in elongated helical conformations. In the majority of polymer molecules, except polystyrenes, polyisoprenes, and polycyclopentadienes, there are randomly disordered regions creating additional volumes inaccessible to solvation with solvent molecules. Cyclopentadiene oligomers formed by the Diels-Alder reaction have in solution the conformation of corrugated bands. The additive scheme for calculating the molar volumes considerably simplifies the determination of the dipole moments and Kerr constants of the compounds for which this scheme has been constructed.     

Phenolic composition ofArtemisia laciniata

V. L. Komarov Botanical Institute, Academy of Sciences of the USSR, Leningrad. Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Branch, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 115–117, January–February, 1990.     

Application of Chromium-Containing Silica for Synthesising Functional Glasslike Materials by the Sol–Gel Method

A new variant of the sol–gel method for synthesising silica glasses and optical composites containing nanoparticles of chromium oxide has been designed. Monolithic gels are produced by mixing preformed silica modified with chromium oxide (Cr₂O₃/SiO₂), with a sol–gel solution containing Si(OC₂H₅)₄, and gelation catalyst ((CH₂)₆N₄ or NH₃). Highly dispersed Cr₂O₃/SiO₂ samples were synthesised through a step-by-step controlled adsorption of vapours of CrO₂Cl₂ and C₆H₁₄ on the surface of fumed silica (A-300) and a subsequent thermal decomposition. With increasing chromium concentration in samples from 0.9 to 5.1 wt.%, the size of chromium oxide nanoparticles increases from 10 to 46 nm. XRD, DTA, TG, IR-spectroscopy and measurements of specific surface area have been used to investigate structural and physico-chemical properties of Cr₂O₃/SiO₂ and xerogels during the course of their thermal transformations up to formation of glasses. A study has also been carried out of optical properties of transparent samples (distribution of refractive index values through cross section of a preform). The glasses synthesised with the aid of Cr₂O₃/SiO₂ have a more uniform distribution of doping constituents and exhibit a larger refractive index in comparison to glasses synthesised through impregnation of silica matrices with a solution of (NH₄)₂Cr₂O₇.